night sweats??? help!

Sooo not sure why but this is the second night in a row I've woken up completely drenched in sweat. I fall asleep FREEZING and wake up drenched in sweat!! It's gross! I NEVER sweat!! I don't have a fever, I haven't been sick, and this is only the second time this has happened. I'm 13DPO this morning and as of last night had a negatove PT so I wonder if it's because AF is coming soon?? Although I've NEVER had this happen. Anyone know what's going on? It's kind of freaking me out... :(